Arthur Stanley Eddington (December 28, 1882 - November 22, 1944) was an English astrophysicist, philosopher and popularizer of science. The Eddington limit, the natural limit to the luminosity of stars, or the radiation generated by accretion onto a compact object, is named in his honor. He is famous for his work regarding the Theory of Relativity. Eddington wrote a number of articles which announced and explained Einstein's theory of general relativity to the English-speaking world. He conducted an expedition to observe the Solar eclipse of 1919 that provided one of the earliest confirmations of relativity, and he became known for his popular expositions and interpretations of the theory. During the 1920s until his death, he increasingly concentrated on what he called "fundamental theory" which was intended to be a unification of quantum theory, relativity, cosmology, and gravitation. He died in 1944 at the age of 61.